Generally, in Space Division Multiple Access (SDMA) systems, an antenna array is used to separate communication devices sharing a common frequency and time channel according to Spatial resolvability. In systems operated in a line of site or low scattering environment, this resolvability can be directly related to the angle of arrival of the various signals. In such an environment, standard techniques may be used to determine the angle of arrival of the various signals. A handover decision or channel reallocation for radio communication devices serviced by such a system is fairly straightforward; when the angle of arrivals of various communication devices are too close then a handover is performed.
In a highly scattering environment, an angle of arrival estimation becomes inaccurate and leads to very poor resolution. With poor resolution, a SDMA system can not accurately determine the location of communication devices, thus, fewer communication devices are allowed to use the same time and frequency channel i.e. lower channel capacity. Additionally, using an angle of arrival estimation in such an environment leads to inaccurate handover decisions. Thus, it would be advantageous to have an alternative criterion for performing handover or channel allocation in a SDMA system operating in a highly scattering environment.